The Squeaker is a device that can be strapped to a tree, rock, etc for purpose of calling predators either for hunting purposes or to capture them on game cameras. I came up with the idea after seeing a similar product online but it didn't have the features that I wanted so I set out to build my own.
It uses a PICAXE 08M2 and activates an off the shelf voice recording module to play back the sound. I use a recording module that can store two different sounds so I have the capability to select between two different ones in the field. DIP switches on the control board allow me to select the different sounds as well as delay settings for each time the sound is played. I can also record new sounds to the device from my iphone by using a audio cable plugged into the headphone jack. This makes changing sounds easy. A CDS was added to give the option of only playing at night or day if you don't want it playing all the time.
Everything runs off 4 AAs and lasts about 10 days in the field playing 24/7. It will last longer if you only have it running at night or only during the day.
I don't have a youtube video yet but can make one if interested. Links to other pics...